Artificial reef



FIG. 1 is a perspective view of an artificial reef embodying thefeatures of the new design;

FIG. 2 is a front elevational view thereof, the left side elevationalview, the right side elevational view, and the rear elevational view areidentical to FIG. 2;

FIG. 3 is an elevational view of the artificial reef midway betweenadjacent outwardly extending members to more clearly illustrate the newdesign;

FIG. 4 is a top plan view thereof; and,

FIG. 5 is a bottom plan view thereof.

The ornamental design for an artificial reef, as shown and described.